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Structural properties and electrochemical behavior of CNT‐TiO 2 nanocrystal heterostructures
Author(s) -
Frank Otakar,
Kalbac Martin,
Kavan Ladislav,
Zukalova Marketa,
Prochazka Jan,
Klementova Mariana,
Dunsch Lothar
Publication year - 2007
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200776158
Subject(s) - anatase , materials science , nanocrystal , electrochemistry , cyclic voltammetry , heterojunction , chemical engineering , monoclinic crystal system , nanocomposite , nanotechnology , electrode , crystal structure , photocatalysis , crystallography , organic chemistry , chemistry , catalysis , optoelectronics , engineering
Different methods of preparation of CNT‐TiO 2 (anatase) heterostructures have been tested in order to obtain information on the relationship between the preparation method, resulting structure of the material and its electrochemical behavior during Li + insertion. The most complete TiO 2 coverage of individual non‐functionalized MWCNT was achieved in block co‐polymer (Pluronic P123) templated TiO 2 thin films. This heterostructure has the highest specific capacity of Li + insertion into TiO 2 lattice to form Li x TiO 2 (688 C/g, x = 0.57), however, this was accompanied by the worst reversibility (76%). On the contrary, electrodeposited TiO 2 on SWCNT covered only bundles of nanotubes and its Li + insertion capacity was 507 C/g ( x = 0.42). However, the reversibility for all electrodeposited samples was almost complete and varied around 98%. Furthermore, Li + insertion behavior studied by the cyclic voltammetry technique showed unambiguously the presence of minute amounts of monoclinic TiO 2 (B) in addition to anatase in samples from both synthesis methods. Thirdly, non‐functionalized MWCNT have been mixed by phase pure anatase nanocrystals of average size 30 nm made by hydrolysis of Ti‐butoxide in ethanol dispersion of CNT. Electrochemical Li + insertion showed x = 0.54 (charge capacity of 652 C/g) with 85% reversibility. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)